This invention relates to a method to grow a crystalline layer on a substrate from a liquid medium, the substrate being moved with respect to the medium during the layer growth.
Such a method is known from the article "A New Method Of Stirring For LPE Growth" by J. C. Brice, J. M. Robertson and H. Van Der Heide of the Philips Laboratories at Eindhoven, published in the review "Journal of Crystal Growth" 30 (1975), pages 375 to 379. According to this known method for growing an epitaxial layer on a flat circular gadolinium-gallium substrate from a liquid medium or solution containing PbO, B.sub.2 O.sub.3, Y.sub.2 O.sub.3 and Fe.sub.2 O.sub.3, this substrate is moved vertically in its own plane with respect to the liquid medium during the growth process of the layer. It should be reminded that this growth method has the advantage that when the substrate is withdrawn slowly from the solution upon the growth process being finished no droplets adhere to the grown surface thus avoiding the formation of mesastructures. More particularly, each point of the substrate surface describes a circumference the diameter 2b of which is smaller than the radius a of the circular substrate so that a controlled liquid movement and a stirring of the solution is obtained. By proceeding in this way only a homogeneous layer of constant thickness is obtained on a central part of the circular substrate having a diameter 2a-4b so that b must be made as small as possible in order to obtain as large as possible a central portion with a constant layer thickness. However, by reducing b the stirring effect is also decreased. In the example described 2a=25 millimeter and b=3.4 millimeter, so that the diameter of the above mentioned central part is smaller than half the diameter of the substrate.